Plating processing line

ABSTRACT

A plating processing line or system includes a plurality of surface processing apparatus including a surface processing apparatus for processing a surface of an object to be treated by introducing a treatment liquid to the surface, and a conveyer unit for conveying the object to be treated, which is disposed between the respective surface processing apparatus linearly or in a curved manner. Each of the surface processing apparatus includes a positioning unit for positioning the object to be treated, which has been conveyed by the conveyer unit to a predetermined position, at which the object is subjected to a pre-plating process or a plating process as a surface processing.

BACKGROUND OF THE PRESENT INVENTION

1. Field of the invention

The present invention relates to a plating processing line or a plating processing system provided with a plurality of surface processing apparatuses or apparatus (called herein as apparatus) for pre-processing or processing a surface of an object to be treated with a treatment liquid introduced to the surface to be treated of the object.

2. Description of the Related Art

In a conventional art, there is provided a plating processing line for plating a cylinder inner peripheral surface of a cylinder block of an engine, for example, such as disclosed in Japanese Patent Application Laid-open No. 8-176898 (Patent Publication 1). According to the plating processing line described in this Patent Publication, a plating process is performed after pre-plating process including a degreasing process, an alkaline etching process, a mixed acid etching process and an anodization process. These processes are performed by conveying a cylinder block gripped by a chuck to treatment stations, respectively.

According to the plating processing line described in the Patent Publication 1, however, the number of pre-plating processes is as many as four processes, which requires relatively long time for the pre-plating process. Furthermore, since the treatment liquids used in the alkaline etching process and the mixed acid etching process differ largely from each other in their characteristics or natures, it is required to sufficiently perform cleaning treatment between the respective processes. Because of these reasons, the plating processing line described in the Patent Publication 1 involves a disadvantage of low manufacturing efficiency.

Furthermore, since the cylinder block using the work chuck must be conveyed by gripping and lifting up them, the effective conveyance is not expected.

Generally, an object to be treated is plated while immersing the object in the treatment liquid in most cases. In such case, since an operation by an operator is inevitable, it is difficult to realize an automated plating processing line.

SUMMARY OF THE PRESENT INVENTION

The present invention was conveived in consideration of the circumstances encountered in the prior art mentioned above, and an object thereof is to provide a plating processing line capable of performing automated various pre-plating processes and plating processes by putting objects to be treated on a conveyance conveyer to thereby improve manufacturing efficiency.

The above and other objects can be achieved according to the present invention by providing a plating processing line comprising:

a plurality of surface processing apparatus including a surface processing apparatus for processing a surface of an object to be treated by introducing a treatment liquid to the surface; and

a conveyer unit for conveying the object to be treated, which is disposed between the respective surface processing apparatus linearly or in a curved manner,

each of the surface processing apparatus including a positioning unit for positioning the object to be treated, which has been conveyed by the conveyer unit to a predetermined position, at which the object is subjected to a pre-plating process or a plating process as a surface processing.

Preferred embodiments of the present invention of the aspect mentioned above may include the following structures.

The surface processing apparatus may includes: a degreasing heating apparatus which performs a degreasing heating process for removing oil from the object to be treated and for heating the object to a temperature for the pre-plating process; an electrolytic etching apparatus which performs an electrolytic etching process for etching the surface of the object; an anodization apparatus which performs an anodization process for forming an oxide film on the surface of the object; and a plating apparatus which performs a plating process for forming a plating film on the surface of the object, in which the degreasing heating apparatus, the electrolytic etching apparatus, the anodization apparatus and the plating apparatus are successively disposed from an upstream side toward a downstream side in the conveyance direction.

In the above embodiment, it may be further desired that the electrolytic etching apparatus, the anodization apparatus and the plating apparatus are configured to spray compressed air to a surface to be treated of the object and recover the treatment liquid adhering to the surface of the object after the electrolytic etching process, the anodization process and the plating process, respectively, and the surface of the object is then subjected to a water washing process.

The anodization apparatus may perform or skip the anodization process depending upon a material forming the object to be treated.

It may be desired that each of the electrolytic etching apparatus and anodization apparatus includes two chemical liquid tanks and configured to perform, in each of the electrolytic etching process and the anodization process, the treatment in one of the tanks at a time when the treatment liquid is renewed in another one tank.

It may be also desired that the same kind of treatment liquids having at least one of concentration and liquid temperature different from each other are respectively used in the electrolytic etching process and the anodization process, and the treatment liquids are switched to be supplied for each process so that the electrolytic etching process and the anodization process are performed in a single surface processing apparatus.

It may be further desired that a plurality of plating apparatus, which perform the plating process at the same time, are disposed on a downstream side of the electrolytic etching apparatus and the anodization apparatus.

In the above aspect, it may be desired that the object to be treated is a cylinder block of an engine, and the surface to be treated of the object is a cylinder inner peripheral surface of the cylinder block.

The conveyer unit may be a roller conveyer provided with a plurality of rollers disposed in parallel with each other so as to convey the object in a horizontal direction through rolling of the rollers.

According to the present invention, an object to be treated or processed conveyed by the conveyer unit (conveyance conveyer) is positioned by the positioning unit of the respective surface processing apparatus, and the pre-plating or plating process is then performed to the object positioned to the predetermined position. Accordingly, various pre-plating and plating processes or processings can be automatically performed to the object positioned on the conveyer unit, thereby improving the manufacturing efficiency.

The nature and further characteristic features or structures will be made clearer from the following descriptions made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a plan view showing a plating processing line or system according to a first embodiment of the present invention;

FIG. 2 is a partial plan view showing an essential portion of FIG. 1 of a surface processing apparatus which functions as an electrolytic etching apparatus, an anodization apparatus or a plating apparatus;

FIG. 3 is a front view illustrating an entire structure of the surface processing apparatus shown in FIGS. 1 and 2;

FIG. 4 is a sectional view showing peripheries of an electrode, an air joint and associated portion thereof in the surface processing apparatus shown in FIG. 3;

FIG. 5 shows a sealing jig or fixture, in which FIG. 5A is a sectional view of a seal member in an expanded condition and FIG. 5B is a sectional view of the seal member in contracted condition; and

FIG. 6 is a plan view showing another plating processing line according to a second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present embodiment will be described hereunder with reference to the accompanying drawings. Further, it is to be noted that terms “upper”, “lower”, “right”, “left” and like terms are used herein in an illustrated state of the accompanying drawings or in an actually usable state.

First Embodiment (FIGS. 1 to 5)

With reference to FIGS. 1 to 3, a plating processing line or system 70 (FIG. 1) is an equipment for performing pre-plating processing and/or plating processing (or treatment) to a cylinder inner peripheral surface 3 (as a surface to be treated) in a cylinder block 1 of an engine (cylinder block of a V-type multi-cylinder engine in the present embodiment) as an object to be treated. The plating processing line 70 includes a plurality of surface processing apparatus (i.e., a degreasing heating apparatus 71, an electrolytic etching apparatus 72, an anodization apparatus 73 and a plating apparatus 74), and a roller conveyer 75 as a conveyance conveyer (conveyer unit).

The degreasing heating apparatus 71, the electrolytic etching apparatus 72, the anodization apparatus 73 and the plating apparatus 74 are successively disposed from an upstream side toward a downstream side of the plating processing line 70.

In the roller conveyer 75, many rollers 76 are arranged in parallel and roll so as to convey the cylinder block 1 in a horizontal direction. The roller conveyers 75 are respectively disposed between the degreasing heating apparatus 71 and the electrolytic etching apparatus 72, between the electrolytic etching apparatus 72 and the anodization apparatus 73 and between the anodization apparatus 73 and the plating apparatus 74.

The roller conveyers 75 are also disposed between the degreasing heating apparatus 71 and a machining apparatus 77 (e.g., cutting apparatus of the cylinder inner peripheral surface 3) located upstream of the degreasing heating apparatus 71, and between the plating apparatus 74 and a machining apparatus 78 (e.g., a honing apparatus of the cylinder inner peripheral surface 3) located downstream of the plating apparatus 74.

The roller conveyers 75 may be continuously disposed in straight or in a curved fashion (in straight in the present embodiment) respectively between the machining apparatus 77, the degreasing heating apparatus 71, the electrolytic etching apparatus 72, the anodization apparatus 73, the plating apparatus 74 and the machining apparatus 78.

If the machining apparatus 77, the degreasing heating apparatus 71, the electrolytic etching apparatus 72, the anodization apparatus 73, the plating apparatus 74 and the machining apparatus 78 are configured to have gradually reduced heights in this order, and if the roller conveyer 75 is configured to incline so as to be gradually lowered from the upstream side toward the downstream side of the plating processing line 70, the roller conveyer 75 can convey the cylinder block 1 to another apparatus or like disposed on the downstream side by its own weight.

The degreasing heating apparatus 71 is a surface processing apparatus for performing surface processing by immersing the cylinder block 1 in the treatment liquid. The electrolytic etching apparatus 72, the anodization apparatus 73 and the plating apparatus 74 are surface processing apparatus for performing surface processing only for the cylinder inner peripheral surface 3 by introducing the treatment liquid only to the cylinder inner peripheral surface 3 of the cylinder 2 in the cylinder block 1.

That is, the degreasing heating apparatus 71 includes a degreasing bath 79, a cleaning bath 80 and a preliminary heating bath 81, to perform a degreasing-heating process. The degreasing heating apparatus 71 also includes a positioning unit, not shown, which positions the cylinder block 1 when the cylinder block 1 is conveyed to a conveyer hatch (cylinder block conveying-in or -out opening) 82 where the roller conveyer 75 is disposed. In the degreasing heating apparatus 71, the positioned cylinder block 1 is gripped by the chucking unit such as the work chuck, not shown, and then, the cylinder block 1 is sequentially immersed in the degreasing bath 79, the cleaning bath 80 and the preliminary heating bath 81. When the cylinder block 1 is immersed in the degreasing bath 79, oil and contamination adhering to the cylinder block 1 are removed, and when the cylinder block 1 is immersed in the cleaning bath 80, the cylinder block 1 is cleaned. When the cylinder block 1 is immersed in the preliminary heating bath 81, the entire cylinder block 1 is uniformly heated to a predetermined temperature.

A treatment bath 85, in which two chemical liquid tanks 83 and liquid supply pumps 84 are disposed, is provided adjacent to the electrolytic etching treatment apparatus 72. The electrolytic etching apparatus 72 introduces the treatment liquid from the chemical liquid tank 83 through the operation of the liquid supply pump 84 only to the cylinder inner peripheral surface 3 of the cylinder 2 in the cylinder block 1 so as to remove impurities and oxide films adhering to the cylinder inner peripheral surface 3, and performs the electrolytic etching process for roughening the cylinder inner peripheral surface 3 to enhance the plating adhesion. The two chemical liquid tanks 83 are provided for the reasin that the electrolytic etching can be continuously performed even if one of these chemical liquid tanks 83 is stopped in operation for renewing the treatment liquid, for example, the other one of the chemical liquid tanks 83 can operate to feed the treatment liquid to the electrolytic etching apparatus 72.

In the electrolytic etching apparatus 72, after the electrolytic etching process has been completed, a valve, not shown, are switched in a state where the cylinder block 1 is attached to the electrolytic etching apparatus 72, and water from a water tank, not shown, is introduced to the cylinder inner peripheral surface 3 by the operation of the liquid supply pump 84, Thus, the cylinder inner peripheral surface 3 is washed and cleaned with water. Here, after the electrolytic etching process and before the washing process, the cylinder inner peripheral surface 3 may be sprayed with compressed air to separate and then recover the treatment liquid which adhers to the cylinder inner peripheral surface 3.

A treatment bath 88 in which two chemical liquid tanks 86 and liquid supply pumps 87 are disposed is provided in adjacent to the anodization apparatus 73. The anodization apparatus 73 introduces the treatment liquid from the chemical liquid tanks 86 by the operation of the liquid supply pump 87 only to the cylinder inner peripheral surface 3 of the cylinder 2 in the cylinder block 1. According to this treatment, the anodization process for forming a porous oxide film on the cylinder inner peripheral surface 3 is performed so as to enhance the plating adhesion. The two chemical liquid tanks 86 are provided so that the anodization can be continuously performed, even if the treatment liquid in one of the chemical liquid tanks 86 is renewed, by introducing the treatment liquid from the other chemical liquid tank 86 to the anodization apparatus 73.

In the anodization apparatus 73, a valve, not shown, is switched in a state where the cylinder block 1 is attached to the anodization apparatus 73 after the anodization process has been completed, and then, water from a water tank, not shown, is introduced to the cylinder inner peripheral surface 3 by the operation of the liquid supply pump 87, thus washing and cleaning the cylinder inner peripheral surface 3 with water. Here, after the anodization process and before the washing, the cylinder inner peripheral surface 3 may be sprayed with compressed air to separate and then recover the treatment liquid which adhers to the cylinder inner peripheral surface 3.

The anodization process may be performed or skipped depending upon material of the cylinder block 1. That is, when the cylinder block 1 is made of aluminum alloy such as low pressure cast material, since silicon content is small and shape thereof is coarse, the anodization process is performed in order to enhance the plating adhesion. On the contrary, when the cylinder block 1 is made of aluminum alloy of die cast material, since the silicon content is high and the shape is dense, sufficient plating adhesion can be obtained only with the electrolytic etching process. Therefore, the anodization process is performed if the cylinder block 1 is made of aluminum alloy such as low pressure cast material, but if the cylinder block 1 is made of aluminum alloy of die casting material, the anodization process may be be skipped.

A treatment bath 91, in which one chemical liquid tank 89 and liquid supply pumps 90 are disposed, is provided in adjacent to the plating apparatus 74. The plating apparatus 74 introduces the treatment liquid from the chemical liquid tank 89 by the operation of the liquid supply pump 90 only to the cylinder inner peripheral surface 3 of the cylinder 2 in the cylinder block 1, and performs the plating process for forming a plating film on the cylinder inner peripheral surface 3.

In the plating apparatus 74, after the plating process has been completed, a valve, not shown, is switched in a state where the cylinder block 1 is attached to the plating apparatus 74, and then, water from a water tank, not shown, is introduced to the cylinder inner peripheral surface 3 by the operation of the liquid supply pump 90, thereby washing and cleaning the cylinder inner peripheral surface 3 with water. Here, after the plating process and before the washing process, the cylinder inner peripheral surface 3 may be sprayed with compressed air to separate and then recover the treatment liquid adhering to the cylinder inner peripheral surface 3.

As shown in FIG. 2, in the electrolytic etching apparatus 72, the anodization apparatus 73 and the plating apparatus 74, work mount table 19 (FIG. 3, to be described later) are provided with positioning pins 92 as positioning unit so that the positioning pins 92 can move upward and downward. The cylinder block 1, which is conveyed to the work mount table 19 of the electrolytic etching apparatus 72, the anodization apparatus 73 or the plating apparatus 74 by the roller conveyer 75, abuts against the positioning pin 92, projecting from the work mount table 19 and is positioned. The electrolytic etching apparatus 72, the anodization apparatus 73 and the plating apparatus 74 respectively perform the electrolytic etching, the anodization and the plating processes for the positioned cylinder block 1. After the respective processings or treatments have been completed and washing is also completed, the positioning pins 92 are moved downward and placed on the work mount tables 19. The cylinder block 1 is then conveyed to the roller conveyer 75 from the work mount table 19.

In the plating processing line of this embodiment, the treatment bath 85 is disposed at a position lower than position of the electrolytic etching apparatus 72, the treatment bath 88 is disposed at a position lower than the anodization apparatus 73, and the treatment bath 91 is disposed at a position lower than to the plating apparatus 74, and accordingly, the treatment liquids in the electrolytic etching apparatus 72, the anodization apparatus 73 and the plating apparatus 74 return to the treatment baths 85, 88 and 91 by their own weights. Here, the chemical liquid tank 83 of the treatment bath 85, the chemical liquid tank 86 of the treatment bath 88 and the chemical liquid tank 89 of the treatment bath 9 1 are similar to a chemical liquid tank 25 (FIG. 4) which will be described hereinlater. The liquid supply pump 84 of the treatment bath 85, the liquid supply pump 87 of the treatment bath 88 and the liquid supply pump 90 of the treatment bath 91 are similar to a liquid supply pump 24 (FIG. 4) which will be described hereinlater.

A surface processing apparatus 10 which functions as the electrolytic etching apparatus 72, the anodization apparatus 73 and the plating apparatus 74 will be explained with reference to FIGS. 3 to 5.

The cylinder inner peripheral surface 3 which is a surface to be treated of the cylinder block 1 of an engine is pre-plated or plated at a high speed by a plating processing (treatment) apparatus 10 illustrated in FIG. 3 while introducing treatment liquid (pre-plating liquid or plating liquid) to the cylinder inner peripheral surface 3. The plating processing apparatus 10 includes an apparatus body 11, an electrode 12, a sealing jig or fixture 13, a work hold jig or fixture 14, an air joint 15, a clamp cylinder 16, and an electrode cylinder 17. In the present embodiment, the cylinder block 1 is a V-type cylinder block for a V-type engine and the cylinder inner peripheral surfaces 3 of a plurality of cylinders 2 formed by the predetermined angle in the cylinder block 1 are concurrently pre-plated or plated.

The apparatus body 11 is firmly installed on a base table 18 and is provided with a work mount table 19 for mounting the cylinder block 1. The cylinder block 1 is mounted on the work mount table 19 with the cylinder head surface 4 directed downward. On the apparatus body 11, the work holding fixture 14 is installed above the work mounting platform so as to be vertically moved by the clamp cylinder 16. The work hold jig 14 is provided with a clamp, not shown. The work hold jig 14 comes into contact with a crankcase surface 5 of the cylinder block 1 mounted on the work mount table 19 at a lowered position. At this time, the clamp of the work hold jig 14 clamps the crankcase surface side portion of the cylinder block 1 so that the cylinder block 1 is retained between the work mount table 19 and the work hold jig 14.

The electrode 12 is supported by an electrode supporting portion 20, which is mounted on the electrode cylinder 17 installed on the apparatus body 11. Through the reciprocation of the electrode cylinder 17, the electrode 12 is inserted into the cylinder 2 of the cylinder block 1 and retracted from the cylinder 2 of the cylinder block 1. With reference to FIG. 3, the left side electrode 12 is inserted into the cylinder 2, and in FIG. 3, the right side electrode 12 is retracted from the cylinder 2. When the electrode 12 is inserted into the cylinder 2 of the cylinder block 1, a seal ring 21 (FIG. 4) such as silicon rubber sheet fitted on the electrode supporting portion 20 comes into contact with the cylinder head surface 4 of the cylinder 1 so as to seal the cylinder head surface 4 side of the cylinder inner peripheral surface 3.

As illustrated in FIG. 3, the sealing jig 13 is mounted on an upper end of the electrode 12 and the air joint 15 is installed on the work hold jig 14. When the electrode 12 is inserted into the cylinder 2 of the cylinder block 1, the sealing jig 13 comes into contact with the air coupling 15 as illustrated in FIG. 4, and air as a fluid is supplied from a main air coupling 22 of the air joint 15 to a sealing member 33 of the sealing jig 13. Hence, the sealing member 33 is expanded only in a radial direction and comes into contact with the cylinder inner peripheral surface 3 of the cylinder block 1 so as to seal the crankcase surface side of the cylinder inner peripheral surface.

A treatment liquid pipe 23 is connected to the electrode supporting portion 20 illustrated in FIG. 3. The treatment liquid pipe 23 is further connected to a liquid supply pump 24 (FIG. 4).

In a state of the crankcase surface side in the cylinder inner peripheral surface 3 of the cylinder block 1 being sealed by the sealing member 33, the liquid supply pump 24 serves to introduce the treatment liquid (pre-plating liquid or plating liquid) reserved in a reservoir tank 25 into the electrode 12 through the treatment liquid pipe 23 and the electrode supporting portion 20. The treatment liquid introduced into the electrode 12, as illustrated in FIG. 4 with arrow, is thereafter introduced into a space 27 partitioned by an outer peripheral surface of the electrode 12 and the cylinder inner peripheral surface 3 of the cylinder block 1 through a slit 26 between a lower plate 34 (described below) of the sealing jig 13 and the electrode 12 and circulates between the space 27 and the reservoir tank 25.

As illustrated in FIGS. 3 and 4, the electrode supporting portion 20 is connected with a lead wire 28, which is connected to a power supply 30. The power supply 30 supplies electric power to the electrode 12 through the lead wire 28 and the electrode supporting portion 20 in such a state that the space 27 is filled with treatment liquid. The power is supplied so that the electrode 12 becomes a negative pole and the cylinder block 1 becomes a positive pole in the pre-plating process, thereby pre-plating the cylinder inner peripheral surface 3 of the cylinder block 1. In the plating process, the power supply is implemented so that the electrode 12 becomes a positive pole and the cylinder block 1 becomes a negative pole so as to plate the cylinder inner peripheral surface 33 to form a plating film on the cylinder inner peripheral surface 3. Pre-plating process and plating process are performed with different treatment liquid and energizing conditions.

FIG. 3 illustrates only one air joint 15, however, the air joints 15 of the number corresponding to that of the electrodes 12 are provided on the work hold jigs 14. Reference numeral 31 in FIG. 3 denotes a cleaning shutter which is operated when cleaning liquid is injected into the cylinder 2 of the cylinder block 1 for cleaning after the pre-plating or plating process is applied onto the cylinder inner peripheral surface 3 of the cylinder block 1, and the electrode 12 is retracted from the cylinder block 1.

Referring next to FIGS. 4 and 5, configurations of the sealing jig 13 and the air joint 15 will be described below.

The sealing jig 13 serves to seal the cylinder inner peripheral surface 3 by contacting the cylinder inner peripheral surface 3 the when treatment liquid is introduced to the cylinder inner peripheral surface 3 of the cylinder block 1. Each of the sealing jigs 13 includes the sealing member 33, the lower plate 34 and a seal base 35.

The sealing member 33, as illustrated in FIG. 5, is made of an expandable material, such as an elastic member like a rubber and is formed into a ring-buoy shape. An inner peripheral portion of the sealing member 33 is opened as an opening portion 49, and an engaging protrusion 36 is formed on both sides in the vicinity of the opening portion 49. An outer peripheral portion 33A of the sealing member 33 is configured to be contactable to the cylinder inner peripheral surface 3 of the cylinder block 1.

The lower plate 34, as illustrated in FIG. 5, a protruded portion 37 is integrally formed in the center of a disc portion 32. A ring member 39 formed with a peripheral groove 38 is disposed on an outer periphery of the protruded portion 37. The protruded portion 37 is formed with main air flow paths 40C and 40D communicating with each other.

A plurality of main air flow paths 40D, for example three main air flow paths 40D, are formed at uniform intervals in a circumferential direction of the lower plate 34. The main air flow paths 40D communicate with the peripheral groove 38 in the ring member 39 and further communicate with main air flow paths 40E formed to communicate with the peripheral groove 38.

A plurality of the main air flow paths 40E, for example three, are formed in the circumferential direction of the ring member 39.

On the disc portion 32 of the lower plate 34, an engaging groove 41 is formed into a ring shape at a boundary portion with the protruded portion 37. The engaging protrusion 36 of the sealing member 33 is engaged with the engaging groove 41. In addition, an internal thread portion 42 for fastening and a bolt through-hole 44 for inserting a bolt 43 are formed on the disc portion 32 and the protruded portion 37. The lower plate 34 is structured so that the disc portion 32 supports a side surface (a lower side surface 33C in FIG. 5) of the sealing member 33 in such a state that the opening portion 49 of the sealing member 33 is fitted onto the ring member 39 and the engaging protrusion 36 of the sealing member 33 is engaged with the engaging groove 41.

In the seal base 35, as illustrated in FIG. 5, a protruded portion 46 is integrally formed in the middle of the disc portion 45, and the protruded portion 46 is formed with a seat portion 47 and a main air flow path 40B. A seal sheet 48 is fitted onto the seat portion 47, and a main air flow path 40A communicating with the main air flow path 40B is formed as a bore extending through the seal sheet 48. The main air flow path 40B is formed so as to communicate with a main air flow path 40C of the lower plate 34.

Further, the disc portion 45 is formed with a recessed portion 50 into which the protruded portion 37 of the lower plate 34 is fitted at an opposite position to the seating portion 47, and an engaging groove 51 is formed into a ring shape outside the recessed portion 50. The engaging protrusion 36 of the sealing member 33 is engaged with the engaging groove 51. A threaded hole 52 for screwing a bolt 43 is formed through the disc portion 45 and the protruded portion 46.

In such a state that the protruded portion 37 of the lower plate 34 is fitted into the recessed portion 50 in the seal base 35, the opening portion 49 of the sealing member 33 is fitted onto the ring member 39 of the lower plate 34, and the engaging protrusion 36 of the sealing member 33 is fitted into the engaging groove 41 on the lower plate 34 and the engaging groove 51 of the seal base 35, the sealing member 33, the lower plate 34 and the seal base 35 are integrated by screwing the bolt 43 into the bolt threaded hole 44 of the lower plate 34 and the bolt threaded hole 52 of the seal base 35, thereby constructing the sealing jig 13.

Under such a condition, the lower plate 34 and the seal base 35 are disposed so as to face each other, and the disc portion 32 of the lower plate 34 supports a side surface (a lower side surface 33C in FIG. 5) of one side of the sealing member 33, while the disc portion 45 of the seal base 35 supports a side surface (an upper side surface 33B) of the other side of the sealing member 33. In addition, with the sealing member 33, the lower plate 34 and the seal base 35 in an integrated state, the main air flow paths 40A, 40B, 40C, 40D and 40E communicating with each other communicate with the interior of the sealing member 33.

As illustrated in FIG. 4, the sealing jig 13 is installed on an upper end of the electrode 12 through a sealing jig mount plate 53 as an insulating member. The sealing jig mount plate 53 is formed into a substantially cruciform shape and an external thread portion 54 for fastening is formed in the center of the sealing jig mount plate 53. A front end portion of the approximately cross-shaped sealing jig mount plate 53 is fixed on the electrode 12 by bolts 55. The external thread portion 54 of the sealing jig mount plate 53 is screwed into an internal thread portion 42 in the lower plate 34 of the sealing fixture 13. The sealing jig 13 constructed by integrating the sealing member 33, the lower plate 34 and the seal base 35 is installed on the sealing fixture mounting plate 53.

The sealing fixture mounting plate 53 is made of non-conductive resin and insulates the lower plate 34 and the seal base 35 made of conductive metal from the electrode 12. The treatment liquid flows toward the slit 26 as shown by an arrow in FIG. 4 passing through a cut-out portion of the sealing jig mount plate 53 having a substantially cruciform shape.

The air joint 15 illustrated in FIGS. 3 and 4 includes a main air supply path 56 in addition to the main air coupling 22 as described above. The main air coupling 22 is connected to an air supply valve and a compressor, not shown, through a main air supply pipe 57. When the electrode 12 is inserted into the cylinder 2 of the cylinder block 1, the air joint 15 comes into contact with the seal sheet 48 of the sealing jig 13 installed on the electrode 12, and the main air supply path 56 is communicated with the main air flow path 40A of the seal sheet 48. Air is supplied from the main air supply path 56 to the main air flow path 40A, and, at this time, air leakage is prevented by the seal sheet 48.

The air supplied from the main air supply path 56 to the main air supply path 40A is introduced into the sealing member 33 through main air flow paths 40B, 40C, 40D and 40E as illustrated in FIG. 5. For the sealing member 33, the upper side surface 33B is supported by the seal base 35 and the lower side surface 33C is supported by the lower plate 34 to regulate expansion of the sealing member 33. Accordingly, as illustrated in FIG. 5A, the sealing member 33 expands only in a radial direction, and the outer peripheral portion 33A of the sealing member 33 comes into contact with the cylinder inner peripheral surface 3 of the cylinder block 1 to seal the crankcase surface 5 side of the cylinder inner peripheral surface 3. Hence, pre-plating processing liquid or plating processing liquid can be prevented from leaking from the space 27 (FIG. 4) partitioned by the cylinder inner peripheral surface 3 and the outer peripheral surface of the electrode 12 toward the crankcase surface 5 side.

When air supply from the main air coupling 22 to the sealing member 33 is shut down, the sealing member 33 contracts in a radial direction and the outer peripheral portion 33A thereof separates from the cylinder inner peripheral surface 3, as illustrated in FIG. 5B.

An apparatus for confirming expansion and contraction of the sealing member 33 is provided on the sealing jig 13 and the air joint 15 as shown in FIG. 4. The confirming apparatuses are a sub air coupling 58 and a sub air supply path 59 on the air joint 15 side, a sub air flow path 60 on the sealing fixture 13 side, an air pressure sensor 61 and a control circuit 62.

The plurality of (for example, three) sub air couplings 58 are arranged on the air joint 15. The plurality of sub air supply paths 59, for example three, are formed on the air joint 15 correspondingly to the sub air couplings 58 so that each of the sub air supply paths 95 communicates with the sub air coupling 58.

The sub air flow path 60 is formed on the seal base 35 of the sealing fixture 13. A plurality of concentric ring grooves 63, for example three, are formed on a top surface of the protruded portion 46 of the seal base 35 correspondingly to the number of the sub air supply paths 59 so that each of the concentric ring grooves 63 communicates with each of the sub air supply paths 59.

A plurality of the sub air flow paths 60 (e.g. three) are radially formed at uniform intervals correspondingly to the number of the ring grooves 63. Each of the sub air flow paths 60 communicates with each of the ring grooves 63. Each of the sub air flow paths 60 is formed with a blow-off hole 64 at an outer peripheral end portion of the seal base 35. The blow-off hole 64 is positioned so as to be closed by the sealing member 33 when the sealing member 33 is expanded and to be opened when the sealing member 33 is contracted, as illustrated in FIG. 5.

The air as a fluid introduced from the sub air coupling 58 provided on the air joint 15 illustrated in FIG. 4 passes through the sub air supply path 59 and blows off from the blow-off hole 64 via the ring groove 63 and the sub air flow path 60 in the sealing jig 13 (FIG. 5). The blow-off of the air through the blow-off hole 64 is performed at a time when the blow-off hole 64 is opened without being closed by the sealing member 33 at contraction of the sealing member 33, as illustrated in FIG. 5B. At this time, air pressure is decreased in the sub air flow path 60, the sub air supply path 59, and the sub air coupling 58.

On the contrary, at expansion of the sealing member 33, as illustrated in FIG. 5A, the air does not blow off through the blow-off hole 64 as a result of the blow-off hole 64 being closed by the sealing member 33, and the air pressure is increased in the sub air flow path 60, the sub air supply path 59, and the sub air coupling 58.

The air pressure sensors 61 illustrated in FIG. 4 are arranged on sub air supply pipes 65, for example three, for introducing the air to the sub air couplings 58. The air pressure sensor 61 detects the air pressure in the sub air flow path 60. From the detected values of air pressures, the expansion or contraction of the sealing member 33 of the sealing fixture 13 can be confirmed. Specifically, it can be confirmed that the sealing member 33 expands and comes into contact with the cylinder inner peripheral surface 3 of the cylinder block 1 to liquid-tightly seal the cylinder inner peripheral surface 3 or that the sealing member 33 contracts and does not come into contact with the cylinder inner peripheral surface 3 of the cylinder block 1 so that the cylinder inner peripheral surface 3 is unsealed.

A detailed example of the confirmation of the sealing by the air pressure will be described below.

In a case where air is supplied to the sub air flow path 60 with the air pressure of 0.10 MPa supplied from the sub air coupling 58, the air pressure in the sub air flow path 60 is 0.09 to 0.10 MPa in the expanded state of the sealing member 33. Further, although the air pressure in the sub air flow path 60 may lower due to malfunction or deterioration of the sealing member 33, when the air pressure is within the range of 0.06 to 0.10 MPa, it can be confirmed that the sealing member 33 expands to contact the cylinder inner peripheral surface of the cylinder block 1 and the cylinder inner peripheral surface 3 is sealed by the sealing member 33.

On the contrary, when the air pressure in the sub air flow path 60 is 0.05 MPa or less, it can be confirmed that the sealing member 33 contracts and does not come into contact with the cylinder inner peripheral surface 3 of the cylinder block 1, and the cylinder inner peripheral surface is not sealed by the sealing member 33, thus confirming that the liquid may leak.

The confirmation of the sealing on the cylinder inner peripheral surface 3 of the cylinder block 1 due to the expansion and contraction of the sealing member 33 is performed over the entire circumferential direction of the sealing member 33 because the plurality of sub air flow paths 60 are formed at uniform intervals in the entire circumferential direction of the seal base 35 (namely, sealing member 33), and for example, three sub air flow paths 60 are formed at uniform intervals of 120 degrees in the circumferential direction of the sealing member 33.

Accordingly, the expanded and contracted states of the sealing member 33 can be confirmed, thus confirming the sealing of the cylinder inner peripheral surface 3 even in the case where deterioration, cracking or breakage occurs at a portion of the sealing member 33 in the circumferential direction. On the other hand, at a portion other than the occurrence portion mentioned above, the sealing member 33 expands normally, and expands insufficiently at defective portion as cracking and does not come into contact with the cylinder inner peripheral surface 3 of the cylinder block 1.

The control circuit 62 illustrated in FIG. 4 fetches values detected by and transmitted from the air pressure sensor 61 to thereby control the operation of the liquid supply pump 24 and the power supply 30. Specifically, the control circuit 62 determines that when a detected value from the air pressure sensor 61 is higher than a predetermined value, the sealing member 33 of the sealing jig 13 expands and contacts the cylinder inner peripheral surface 3 of the cylinder block 1 and the cylinder inner peripheral surface 3 is then sufficiently sealed. At this time, the control circuit 62 operates to start the liquid supply pump 64 so as to supply the treatment liquid to the space 27 partitioned by the cylinder inner peripheral surface 3 and the outer peripheral surface of the electrode 12, then drives the power supply 30 so as to supply electric power to the electrode 12 and performs pre-plating or plating processing to the cylinder inner peripheral surface 3.

The control circuit 62 determines that when a value detected by and transmitted from the air pressure sensor 61 is the predetermined value or lower, the sealing member 33 of the sealing jig 13 does not expands properly, and otherwise, contracts and does not come into contact with the cylinder inner peripheral surface 3. The cylinder inner peripheral surface 3 is sealed incompletely. In this case, the control circuit 62 does not drive the liquid supply pump 24 nor the power supply 30, or stops the driving the liquid supply pump 24 and the power supply 30.

The operation of such configured plating processing line or system 70 will be explained hereunder.

First, as shown in FIG. 1, the cylinder block 1 is subjected to the degreasing process in the degreasing bath 79 of the degreasing heating apparatus 71, subjected to the hot water washing process in the cleaning bath 80, and also subjected to the preliminary heating process in the preliminary heating bath 81. The processing or treatment conditions in the degreasing, washing and preliminary heating processes are shown in Table 1. In the degreasing process, the degreasing agent of 20 to 50 g/liter is used as the treatment liquid, and the entire cylinder block 1 is immersed in the treatment liquid for the treatment time of 0.5 to 3 minutes at a liquid temperature of 40 to 80° C. When the cylinder block 1 is immersed in the treatment liquid, the cylinder block 1 may be swung, and an ultrasonic oscillator may be used so as to enhance the cleaning effect. This degreasing process is highly detergent and has an excellent water washability, and thus, oil or contamination adhering to the cylinder block 1 can be removed without corroding the base metal. In the hot water washing process, the hot water of 50 to 90° C. is used, and the entire cylinder block 1 is immersed in the hot water and cleaned for 0.5 to 3 minutes. In the preliminary heating process, the hot water of 50 to 90° C. is used, and the entire cylinder block 1 is immersed in the hot water and heated for 0.5 to 3 minutes. By performing the preliminary heating, the cylinder block 1 is uniformly heated to a predetermined temperature. Therefore, the electrolytic etching time by the electrolytic etching apparatus 72 can be shortened, and the etching amount can be uniformed.

TABLE 1 Process or water Preliminary Process Degreasing washing heating Treatment Degreasing → Hot → Hot water liquid agent water 20 to 50 g/l Liquid 40 to 80° C. 50 to 50 to 90° C. Temperature 90° C. Treatment 0.5 to 3 min 0.5 to 3 min 0.5 to 3 min time Purpose of Degreasing Cleaning Heating Treatment

Next, the cylinder inner peripheral surface 3 of the cylinder block 1 is subjected to the electrolytic etching by the electrolytic etching apparatus 72. In this process, electricity is supplied so that the electrode 12 (FIG. 3) becomes a negative pole and the cylinder block 1 becomes a positive pole. Phosphoric acid of 100 to 500 g/liter is used as the treatment liquid, and the treatment is performed at liquid temperature of 60 to 90° C. for 0.5 to 3 minutes at liquid flow rate of 10 to 40 cm/sec and under energization condition (current density) of 10 to 80 A/dm².

By the electrolytic etching, impurities and oxide films adhering to the cylinder inner peripheral surface 3 are removed, in addition to that eutectic silicon in aluminum alloy is made to project from the surface to roughen the cylinder inner peripheral surface 3. Therefore, the plating adhesion can be enhanced due to anchor effect. At that time, if the cylinder block 1 is made of aluminum alloy of die casting material, the silicon content is high and the shape is dense, and thus, sufficient plating adhesion can be obtained only with electrolytic etching. If the cylinder block 1 is made of aluminum alloy of low pressure cast material, the silicon content is small and shape thereof is coarse. Therefore, the plating adhesion can be enhanced by adding the following anodization.

The cylinder block 1 which has been subjected to the electrolytic etching is attached to the electrolytic etching apparatus 72, the electrode 12 is inserted into the cylinder 2, and the cylinder block 1 is then subjected to the water washing in a state where the cylinder inner peripheral surface 3 on the side of the crank case face 5 is sealed by the sealing jig 13. If the cylinder block 1 is made of aluminum alloy of low pressure casing material, the same chemical (phosphoric acid) as that of the electrolytic etching is used in the following anodization. Thus, the water washing process can be simplified. If the cylinder block 1 is made aluminum alloy of die casting material, the next anodization will be skipped. Therefore, the cylinder block 1 made of aluminum alloy of low pressure cast material is conveyed to the anodization apparatus 73, and the cylinder block 1 made of aluminum alloy of die casting material is conveyed to the plating apparatus 74.

TABLE 2 High Process or Electrolytic speed process etching Anodization plating Treatment Phosphoric → Phosphoric → Nickel → liquid acid (A) → acid (B) → sulfate (C) 100 to 500 g/l 5 to 70 g/l 300 to 700 g/l Liquid 60 to 90° C. 30 to 70° C. 40 to temperature 80° C. Treatment 0.5 to 3 min 0.5 to 3 min 5 to 10 min time Liquid flow 10 to 40 cm/sec 10 to 40 cm/sec 50 to 80 cm/sec rate Energization 10 to 80 A/dm² 5 to 30 A/dm² 10 to 30 A/dm² × condition 0.5 to 1 min 30 to 70 A/dm² × 0.5 to 1 min 80 to 120 A/dm² × 4 to 8 min Treatment Etching Oxide film Plating purpose formation film formation (In the above Table 2, (A), (B) and (C) denote “water washing processes”.)

The cylinder inner peripheral surface 3 of the cylinder block 1 made of aluminum alloy of low pressure die casting material is subjected to the anodization by the anodization apparatus 73. In this process, the electricity is supplied so that the electrode 12 becomes a negative pole and the cylinder block 1 becomes a positive pole. Phosphoric acid of 5 to 70 g/liter, which is the same kind as that used in the electrolytic etching and has a different concentration, is used as the treatment liquid, and the treatment is performed at liquid temperature of 30 to 70° C. for 0.5 to 3 minutes at liquid speed of 10 to 40 cm/sec, and under the energization condition (current density) of 5 to 30 A/dm².

By carrying out the anodization process, a porous oxide film is formed on the cylinder inner peripheral surface 3, and the plating adhesion can be enhanced. The cylinder block 1 which has been subjected to the anodization process is then subjected to the water washing process in a state where the cylinder block 1 is attached to the anodization apparatus 73, the electrode 12 is inserted into the cylinder 2, and the cylinder inner peripheral surface 3 on the side of the crank case surface 5 is sealed by the sealing jig 13.

The cylinder inner peripheral surface 3 of the cylinder block 1 which has been subjected to the pretreatment (degreasing heating; electrolytic etching and anodization; or degreasing heating and electrolytic etching) is then subjected to the plating process by the plating apparatus 74. This process is performed so that the electrode 12 becomes a positive pole and the cylinder block 1 becomes a negative pole, and that electricity is supplied in three stages, i.e., low, intermediate and high strength. The treatment is performed by using nickel sulfate of 300 to 700 g/liter as the treatment liquid, at liquid temperature of 40 to 80° C. for 5 to 10 minutes at liquid flow rate of 50 to 80 cm/sec and under energization condition (current density, time) of 10 to 30 A/dm²×0.5 to 1 minutes (low), 30 to 70 A/dm²×0.5 to 1 minutes (intermediate), and 80 to 120 A/dm²×4 to 8 minutes (high). The cylinder block 1 having a predetermined plating film formed on the cylinder inner peripheral surface 3 is attached to the plating apparatus 74, the electrode 12 is inserted into the cylinder 2, and the cylinder inner peripheral surface 3 on the side of the crank case surface 5 is sealed with the sealing jig 13. In this state, the cylinder 1 is subjected to the water washing process and thus the processes have been completed.

Herein, the respective cylinder inner peripheral surfaces 3 of the cylinder blocks 1 may be sprayed with compressed air so as to separate and or recover the treatment liquid adhering to the cylinder inner peripheral surfaces 3 after the completion of the electrolytic etching and before the completion of the water washing in the anodization apparatus 73, and after the completion of the plating and before the water washing, in the plating apparatus 74, respectively. Such recovering process is also performed in a state where the cylinder block 1 is attached to the electrolytic etching apparatus 72, the anodization apparatus 73 or the plating apparatus 74, the electrode 12 is inserted into the cylinder 2, and the cylinder inner peripheral surface 3 on the side of the crank case surface 5 is sealed by the sealing jig 13.

According to the first embodiment of the plating processing line (system) of the configuration described above, the following functions and advantageous effects (1) to (7) may be attained.

(1) According to the plating processing line 70, the degreasing heating apparatus 71, the electrolytic etching apparatus 72, the anodization apparatus 73 and the plating apparatus 74 serve to position the cylinder block 1 conveyed by the roller conveyer 75 by the positioning unit (e.g., positioning pin 92 (FIG. 2)), and the plate processing line 70 then performs the pre-plating (degreasing heating, electrolytic etching, or anodization) or plating on the thus positioned cylinder block 1. Therefore, various pre-plating and the plating processes can be automated by putting the cylinder block 1 on the roller conveyer 75, thereby improving the manufacturing efficiency. As a result, the manufacturing efficiency of the manufacturing line of the cylinder block 1 can be further improved, and the manufacturing cost can be reduced by connecting the plating processing line 70 to the automated machining line which may include the machining apparatus 77 and 78 and the like.

(2) The roller conveyers 75 are continuously disposed in straight or in curved manner between the degreasing heating apparatus 71, the electrolytic etching apparatus 72, the anodization apparatus 73 and the plating apparatus 74, to thereby effectively convey the cylinder block 1. Therefore, the cost required for facility or equipment for conveyance can be reduced, and the effective conveyance can be also realized.

(3) In the plating processing line 70, the cylinder inner peripheral surface 3 of the cylinder block 1 is plated through four kinds of processes, i.e., the degreasing heating process, the electrolytic etching process, the anodization process and the plating process. On the other hand, the he conventional plating processing line requires five kinds of processes, i.e., the degreasing process, the alkaline etching process, the mixed acid etching process and the anodization process. Therefore, with the plating processing line 70 of the present embodiment, the number of processes concerning the plating can be reduced, thereby improving the producing efficiency.

(4) In the plating processing line 70, the preliminary heating is performed in the degreasing heating apparatus 71 before the electrolytic etching process performed by the electrolytic etching apparatus 72. Therefore, the cylinder block 1 can uniformly heated to the predetermined temperature. As a result, the electrolytic etching time can be shortened, and the etching amount can be equalized.

(5) The treatment liquid used in the electrolytic etching process by using the electrolytic etching apparatus 72 and the treatment liquid used in the anodization process by using the anodization apparatus 73 are the same kind of chemical (e.g., phosphoric acid). Therefore, the water washing carried out after the electrolytic etching process and before the anodization process can be simplified.

(6) In the plating processing line 70, only the cylinder block 1 made of aluminum alloy such as low pressure cast material is subjected to the anodization by the anodization apparatus 73, and the cylinder block 1 made of aluminum alloy of die casting material is not subjected to the anodization. As described above, the plating processing line 70 is configured to correspond to the cylinder blocks 1 even made of different materials, so that the number of processes can be reduced especially in the case of the cylinder block 1 made of aluminum alloy of die casting material in which the anodization process is skipped, thus improving the manufacturing efficiency.

(7) After the completion of the electrolytic etching process and before the completion of the water washing process in the electrolytic etching apparatus 72, also after the completion of the anodization process and before the water washing process in the anodization apparatus 73, and also after the completion of the plating process and before the water washing process in the plating apparatus 74, the respective cylinder inner peripheral surfaces 3 of the cylinder blocks 1 may be sprayed with compressed air, so that treatment liquid adhering to the cylinder inner peripheral surfaces 3 is separated and recovered or collected. In this case, the amount of treatment liquid consumed and the amount of treatment liquid wasted can be reduced. Further, since the water washing time can be shortened, the manufacturing efficiency can be improved.

Second Embodiment (FIG. 6)

FIG. 6 is a plan view showing a second embodiment of the plating processing line or system according to the present invention. In the second embodiment, the same reference numerals are added to members or portions corresponding to those of the first embodiment, and explanation thereof will be simplified or omitted.

A plating processing line 100 of the second embodiment is different from the plating processing line 70 of the first embodiment in that the electrolytic etching process and the anodization process are performed by a single surface processing apparatus, i.e., by an electrolytic etching/anodization apparatus 101.

In this case, in the electrolytic etching process and the anodization process, the same kind of treatment liquid is used but at least one of concentration and liquid temperature differs. Accordingly, the treatment liquid is supplied to the electrolytic etching/anodization apparatus 101 from a chemical liquid tank 83 of a treatment bath 85 when the electrolytic etching process is performed, and the treatment liquid is supplied to the electrolytic etching/anodization apparatus 101 from a chemical liquid tank 86 of the treatment bath 88 when the anodization process is performed by the electrolytic etching/anodization apparatus 101.

Herein, the supply of the respective treatment liquids is switched to the electrolytic etching/anodization apparatus 101. The electrolytic etching/anodization apparatus 101 is composed of the surface processing apparatus 10 shown in FIGS. 3 to 5 like the electrolytic etching apparatus 72 and the anodization apparatus 73.

According to the second embodiment, the following effect (8) is attained in addition to the effects (1) to (7) of the first embodiment.

(8) The electrolytic etching process and the anodization process can be performed by the electrolytic etching/anodization apparatus 101, which is the single surface processing apparatus. Therefore, one surface processing apparatus can be eliminated, and the plating processing line 100 can be reduced in size. Herein, the treatment time of the electrolytic etching process and the anodization process is reduced to ½ of the treatment time of the plating process. Therefore, in a case where these these two processes are performed with a single apparatus, the plating apparatus 74 does not require the standby time, and deterioration in productivity can be avoided.

It is further to be noted that the present invention has been explained with reference to the preferred embodiments described above, but the present invention is not limited thereto and many other changes and modifications may be made without departing from the scopes of the appended claims.

For example, in the plating processing line 70 of the first embodiment, a plurality of (e.g., two) plating apparatus 74 may be provided on the downstream side of the electrolytic etching apparatus 72 and the anodization apparatus 73 so as to perform the plating process at the same time. In this case, the plurality of plating apparatus 74 may be provided on the upstream and downstream sides of the straight roller conveyer 75, or the plurality of plating apparatus 74 may be disposed respectively for a plurality of branched roller conveyers 75.

In this example, the following effect would be attained. That is, the plating process by the plating apparatus 74 requires two times of both of the treatment time of the electrolytic etching process by the electrolytic etching apparatus 72 and the anodization process by the anodization apparatus 73. Accordingly, when the electrolytic etching apparatus 72 performs the electrolytic etching process and the anodization apparatus 73 performs the anodization process respectively, a standby time may be caused between these processes. On the other hand, the location of the plural plating apparatus 74 prevents the standby time from being caused, thereby improving the efficiency in productivity.

Furthermore, although the embodiments have been described based on the assumption that the cylinder block 1 is the V-type cylinder block of the V-type multi-cylinder engine, the present invention may be also applied to a cylinder block of a single-cylinder engine or an in-line multi-cylinder engine, or the present invention may also be applied to parts, other than the cylinder block, which are subjected to the plating processing.

In addition, the conveyance conveyer is not limited to the roller conveyer 75, and other conveyer units such as a belt conveyer may be used. 

1. A plating processing line comprising: a plurality of surface processing apparatus including a surface processing apparatus for processing a surface of an object to be treated by introducing a treatment liquid to the surface; and a conveyer unit for conveying the object to be treated, which is disposed between the respective surface processing apparatus linearly or in a curved manner, each of the surface processing apparatus including a positioning unit for positioning the object to be treated, which has been conveyed by the conveyer unit to a predetermined position, at which the object is subjected to a pre-plating process or a plating process as a surface processing.
 2. The plating processing line according to claim 1, wherein the surface processing apparatus includes: a degreasing heating apparatus which performs a degreasing heating process for removing oil from the object to be treated and for heating the object to a temperature for the pre-plating process; an electrolytic etching apparatus which performs an electrolytic etching process for etching the surface of the object; an anodization apparatus which performs an anodization process for forming an oxide film on the surface of the object; and a plating apparatus which performs a plating process for forming a plating film on the surface of the object, in which the degreasing heating apparatus, the electrolytic etching apparatus, the anodization apparatus and the plating apparatus are successively disposed from an upstream side toward a downstream side in the conveyance direction.
 3. The plating processing line according to claim 2, wherein the electrolytic etching apparatus, the anodization apparatus and the plating apparatus are configured to spray compressed air to a surface to be treated of the object and recover the treatment liquid adhering to the surface of the object after the electrolytic etching process, the anodization process and the plating process, respectively, and the surface of the object is then subjected to a water washing process.
 4. The plating processing line according to claim 2, wherein the anodization apparatus is allowed to perform or skip the anodization process depending upon a material forming the object to be treated.
 5. The plating processing line according to claim 2, wherein each of the electrolytic etching apparatus and anodization apparatus includes two chemical liquid tanks and configured to perform, in each of the electrolytic etching process and the anodization process, the treatment in one of the tanks at a time when the treatment liquid is renewed in another one tank.
 6. The plating processing line according to claim 2, wherein the same kind of treatment liquids having at least one of concentration and liquid temperature different from each other are respectively used in the electrolytic etching process and the anodization process, and the treatment liquids are switched to be supplied for each process so that the electrolytic etching process and the anodization process are performed in a single surface processing apparatus.
 7. The plating processing line according to claim 2, wherein a plurality of plating apparatus, which perform the plating process at the same time, are disposed on a downstream side of the electrolytic etching apparatus and the anodization apparatus.
 8. The plating processing line according to claim 1, wherein the object to be treated is a cylinder block of an engine, and the surface to be treated of the object is a cylinder inner peripheral surface of the cylinder block.
 9. The plating processing line according to claim 1, wherein the conveyer is a roller conveyer having a plurality of rollers disposed in parallel with each other so as to convey the object in a horizontal direction through rolling of the rollers. 